Norwood

[protour73]

Originally Posted by GregWeld

Okay -- and I see another possible issue.... ASSUMING you're running an MSD box... since I see you've put on a GM weatherpak connector on the distributor.

The Black/Violet wire is negative (-) while the Black/Orange is postive (+). The wires that come out of the MSD are Violet(+) and Green (-). The 2-Pin connectors are designed to only connect one way so the wiring cannot be switched. If for some reason the connectors are changed, be sure the wires are connected with matching polarity. If they are not, the engine may or may not start, but if it does the timing will be inconsistent and it will run rough and not accelerate.

FYI Greg, that weatherpak connector is stock for MSD distributors.

[Sieg]

Originally Posted by GregWeld

I've always USUALLY found that it's something SUPER SIMPLE that only makes sense after it's accidentally discovered. In the mean time --- SO F'N FRUSTRATING!

I KNOW!!!!

[GregWeld]

Originally Posted by protour73

FYI Greg, that weatherpak connector is stock for MSD distributors.

Not on all of 'em - on some maybe -- like the "ready to run" -- but for years the MSD distributors have come standard with a two wire non weather pack (in fact a crappy little piece) connector.

I've been clipping them off and switching over to the weather pack style because it's such a superior connector.

Even the MSD boxes have the trigger wires (black with violet and black with green) pre-wired with the "other half" of the crappy little connector.


Not arguing here -- just sayin'

[glassman]

The carb could have an internal vacuum leak, although I do not know how to check that.(I had symptoms similar to this on my boat)

Also, are the valve adjust on this any harder than the KTM's?

Mike

[Sieg]

Originally Posted by glassman

The carb could have an internal vacuum leak, although I do not know how to check that.(I had symptoms similar to this on my boat)

Also, are the valve adjust on this any harder than the KTM's?

Mike

The vacuum guage reading was similar during the symptoms 10"-11" not sure if a vacuum leak that's enough to create these problems would be detectable on the guage.

I guess I could spray it down with starting fluid while running but I'm a little gun-shy about fires right now!

I'm getting ready to go through the tach wiring to verify the power and ground points. That has been haunting me so it's time to eliminate it.

KTM valve adjustments on the LC8 and RC8 are a little more complicated but not once you access the valve covers since they use shims.

It takes a while to get to this point and the covers are still not removable!


My '83 750 & '84 500 Honda V-Four Interceptor motors were a breeze as were the XR500's.

[carbuff]

Your suggestion to spray around the vacuum ports is a good one. Also, if you basically have the blades closed, what happens if you hold your hands over the carb to prevent most of the air from going through? If is still runs, air is getting in from somewhere else...

I can't tell from your picture, but are there vacuum hoses coming off the carb? If so can you just remove them and plug everything to rule out as much as you can there?

Another place that air can be pulled in is through the intake manifold gasket if it wasn't sealed well down in the valley area. Hard to tell with it all installed though.

I'm not very knowledgeable on distributors, but is it possible for you to completely lock the advance in some way to at least eliminate advance from the equation as you are trying to adjust the carb?

And time to ask the simplest of questions. Since it's running ok, I doubt this is a problem, but... You have double and triple checked the plug wires are ordered correctly, right?

And one more I can think of... When you pulled the distributor, everything looked ok with the gear, correct? I know a car which I had in the past started showing erratic timing when the gear was being eaten alive by the cam shaft due to using the wrong gear... :\

Just brainstorming as I type. Not sure much is helpful, but looking for outside the box ideas... Good luck!

[Sieg]

Originally Posted by carbuff

Your suggestion to spray around the vacuum ports is a good one. Also, if you basically have the blades closed, what happens if you hold your hands over the carb to prevent most of the air from going through? If is still runs, air is getting in from somewhere else...

I can't tell from your picture, but are there vacuum hoses coming off the carb? If so can you just remove them and plug everything to rule out as much as you can there?

Another place that air can be pulled in is through the intake manifold gasket if it wasn't sealed well down in the valley area. Hard to tell with it all installed though.

I'm not very knowledgeable on distributors, but is it possible for you to completely lock the advance in some way to at least eliminate advance from the equation as you are trying to adjust the carb?

And time to ask the simplest of questions. Since it's running ok, I doubt this is a problem, but... You have double and triple checked the plug wires are ordered correctly, right?

And one more I can think of... When you pulled the distributor, everything looked ok with the gear, correct? I know a car which I had in the past started showing erratic timing when the gear was being eaten alive by the cam shaft due to using the wrong gear... :\

Just brainstorming as I type. Not sure much is helpful, but looking for outside the box ideas... Good luck!

As weak as it feels at idle I'd guess covering it would kill it quick. But haven't tried it.
No vac ports on this carb.
Motor is fresh, intake sealed with The Right Stuff and Edelbrock gaskets.
Mechanical advance is pretty simple and with the firmer springs installed with no change in symptoms I don't think that's it.
Plug wires are right:


Distributor gear looks like this:


Appreciate the brainstorming............like Greg said, it will most likely be something stupid simple and I'll feel stupid.............again.

I did trace the tach wiring and it's grounded to the instrument panel ground. The MSD is pretty sensitive to ground so I'm going to run it to a dedicate engine ground just to be sure. Though previously it was working with this wiring configuration.

[Vince@Meanstreets]

Originally Posted by Sieg

Distributor has a silver and blue spring currently, it was running fine with that set up but I found out the transfers slots were not exposed so I set them at .025 and had a 2K idle. The symptoms started when I loosened the distributor to retard the initial timing from 16* to a number that would deliver an acceptable idle speed and carb settings.

I can get it below 1K with little or no transfer slot exposure (.025 is spec). Problem was flat power as the clutch engaged.

are you getting idle signal from the secondary bores?

[fleetus macmullitz]

Cut your losses and trade it for a used SB2.

[Sieg]

Originally Posted by Vince@MSperfab

are you getting idle signal from the secondary bores?

Fuel screws and throttle shaft idle screw impact idle, secondary throttle shaft adjustment seems more sensitive than primary.

When it was fired after running the valves yesterday it's feels normal above 2K rpm, between 1-2K is where it's weak and vague. While getting it up to temp when it would go below 1K heading to a stall, pumping the pedal lightly to catch it resulted in a backfire and little carb fire. That's leading me to think it "could be electrical, somewhat similar trait to the weak distributor ground.

After reading MSD's troubleshooting list http://www.msdignition.com/troubleshooting.aspx I'm going to check the magnetic pickup value and verify conditions listed in timing fluctuations, and improve tach ground or just eliminate the tach right now.

My SnapOn Timing light pick up clamp isn't directional but I'll experiment with flipping it just because.